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Fiber optic telephone line extension system

  • US 5,666,402 A
  • Filed: 04/05/1994
  • Issued: 09/09/1997
  • Est. Priority Date: 04/05/1994
  • Status: Expired due to Term
First Claim
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1. An apparatus for providing telephone communication between a communication network and a remote station, said apparatus comprising:

  • a base modem for communicative connection to said communication network;

    a remote modem for direct communicative connection to a first user instrument at said remote station; and

    a fiber optic link connecting said base modem to said remote modem such that telephone communication between said communication network and said first user instrument is provided via said fiber optic link, said fiber optic link being transparent to said communication network and said first user instrument;

    wherein said remote modem provides a first two-way communication path between said first user instrument and the fiber optic link, said remote modem including;

    a first telephone interface for direct communicative connection to said first user instrument and for emulating the communication network to said first user instrument;

    a fiber optic controller/driver for transmitting and receiving digitally modulated signals over said fiber optic link;

    first audio processing means connected between said first telephone interface and said fiber optic controller/driver such thata first audio signal received from said first user instrument by said first telephone interface is converted to a first digitally modulated signal by modulation means in said first audio processing means and transmitted to said fiber optic link by said fiber optic controller/driver, anda second digitally modulated signal received from said fiber optic link by said fiber optic controller/driver is converted to a second user audio signal by demodulation means in said first audio processing means and transmitted to said first user instrument by said first telephone interface, the modulation means and demodulation means each receiving clock signals from said fiber optic controller/driver;

    separate paths within said first two-way communication path for a ring logic and an off-hook logic wherein said fiber optic controller/driver facilitates the transmission of said ring and off-hook logic in separate digital channels over the fiber optic link;

    a ring generator for generating a ring signal to said first user instrument;

    a relay for connecting said first user instrument to either said first telephone interface or said ring generator; and

    a ring circuit forresponding to the ring logic from said fiber optic controller/driver by causing the relay to connect the first user instrument to said ring generator, andresponding to an off-hook condition received from said first user instrument by causing the relay to connect the first user instrument to the first telephone interface and causing the off-hook logic to be transmitted to said fiber optic controller/driver.

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